Get customer by externalId
Returns very basic information about a customer based on their external customer ID. For you to be able to retrieve a customer, they must have at least one session initiated with your API-Key. Please note that this endpoint returns an array of objects because we cannot ensure the uniqueness of the external customer ID.
Authorizations
Your secret API key, passed as Authorization: Api-Key <secret key>, for example Authorization: Api-Key sk_test_key. Secret keys are prefixed with sk_test_ (sandbox) or sk_live_ (production) and must only be used server-side. Never expose them in client code. Find your keys on the API keys page of the dashboard. See Authentication.
Response
Successful response: an array of customer objects matching the external customer ID.